Need with finding the missing length

Factor -8x3-2x2-12x-3 by grouping what is the resulting expression?

How many kilometers are equal to 5 miles? use 1 mile ≈ 1.61 kilometers. !

The means and mean absolute deviations of the individual times of members on two 4x400-meter relay track teams are shown in the table below. means and mean absolute deviations of individual times of members of 4x400-meter relay track teams team a team b mean 59.32 s 59.1 s mean absolute deviation 1.5 s 245 what percent of team b's mean absolute deviation is the difference in the means? 9% 15% 25% 65%